A chemical or enzymatic drain cleaner is often the first choice to remove blockages caused by hair, grease, soap, human waste or other foreign materials. It's easy and inexpensive to use, but can cause problems if you choose the wrong cleaner for the type of clogged drain you have, or if you use the product incorrectly.
Damage to Pipes or Surrounding Surfaces
Chemical drain cleaners react with the blockage material by creating heat that disintegrates it. Designed to be denser than water, they are more likely to splash and corrode surrounding surfaces. To reduce damage to surrounding areas like porcelain, stainless steel and aluminum faucets, pour the cleaner as close to the drain as possible and use only the minimum amount necessary. Most require that you either add water to the cleaner or add cleaner to the water. Do so carefully and slowly to reduce splashing. Avoid pouring the cleaner into a plastic or porcelain basin to reduce the chance of cracking it.
Be aware of what type of piping you have. Chemical drain cleaners can soften soft plastic pipes (PVC). They can also cause additional damage to already old and corroded pipes. You may have to use an enzymatic drain cleaner to prevent damage to your pipes. They tend to be less corrosive, but they're also less effective at dissolving blockages. A manual drain cleaner like a drain snake is also an option.
Chemical drain cleaners tend to release vigorous gases. To prevent breathing in the fumes, use drain cleaners only in well-ventilated areas and don't stand close and watch as it works.
Avoid mixing different types of drain cleaner. If one type doesn't work, don't use another type since you could create a chemical reaction like a dangerous cloud of toxic gas or an eruption of chemicals from the drain. Mixing drain cleaners could also make it impossible to later unblock the drain manually with a drain snake due to the risk of exposure to unknown chemical mixtures.
It's crucial that you don't mix drain cleaner with any cleaning product containing bleach. This could create chlorine gas that is deadly to humans and animals.
Drain cleaners tend to be affordable to use, but some of the more budget-conscious may be tempted to buy the cheapest product available. The cheaper ones, such as those found in discount dollar stores, tend to be ineffective. The strength of their mixtures are often inconsistent so you'll never know how potentially toxic they are. It's best to go with a medium- to high-priced cleaner from a reputable store.
Danger to Pets
Liquid drain cleaner can pose a danger to pets who often like to drink puddles of water in sinks, tubs and toilets. Even a small amount of the product is poisonous and can kill your pet if he or she drinks it. After using any liquid drain cleaner, make sure to clean the surrounding area thoroughly. If possible, keep your pet away from the toilet, sink or tub for a couple of days.